A lot of men and their doctors have traced their back problems to sitting on their wallet in their back pocket, so yes, sitting cocked slightly sideways in your sewing chair can cause problems. If you can teach yourself to use both feet on the controller and alternate frequently, it will probably help. I've found the most helpful people for these kinds of pain are physical therapists. They will put hands on to identify the painful muscles or nerves involved and advise you of a program to relieve the pain and prevent it. Then it's just up to us to actually put the new information into practice. And keep doing it. Easier said than done. Sort of like dieting...